Communication system



y 38- G. w. WATSON 2,116,649

COMMUNICATION SYSTEM Filed Jan. 16, 1935 yah/LLVENEOR.

I BY WA ATTORNEYS.

Patented May 10, 1938 UNITED STATES PATENT QFFIWE COMIVIUNICATION SYSTEM York Application January 16, 1935, Serial No. 2,062

3 Ulalms.

' The present invention relates to a communication system and more particularly to printing telegraph systems applicable to radio and line transmission.

The invention embodies the use oi synchronized disks or distributors at the transmitting and receiving stations for completing the transmitting and receiving circuits respectively, similar to the synchronization system disclosed in the application Serial No. 684,362, filed August 9, 1933. Heretofore, similar systems employed means for transmitting independent and different character impulses to activate the receiving circuits for each character to be transmitted and recorded.

In the present invention a'continuous or prolonged impulse is employed and transmitted during the intervals transmission of characters is not occurring, so that when used in conjunction with the aforementioned synchronized disks, the characters at the receiver are recorded which correspond to the transmitted characters by discontinuing the continuous impulse or causing a.

void impulse at the proper moment in the continuous cycle to represent tne particular character to be transmitted.

The present invention will be explained in conjunction with a single impulse system, in which the diiferent characters to be transmitted are represented by single impulses which are definitely allocated during timed intervals to control the transmitter accordingly. Broadly, the system involves the shifting of the character impulse along the axis of a timed scale, the position of the impulse thereon determining the character to be selected.

The single impulses originated representing the characters are adapted to discontinue a continuous or prolonged impulse radiated by the transmltter of the system at the corresponding time the particular pulses are initiated. The continuous impulse transmitted is adapted to maintain the receiver inoperative, by way of example, one form of which is shown as a photo cell circuit that remains activated by a light source energized by the continuous impulses. The'discontinuance of the pulse at a particular timed period within a timed interval is adapted to energize the receiving unit at that period to record the particular character.

Numerous advantages are to be obtained from a system of this type employing the disclosed principle, one of which is the reduction of natural or artificial interference usually present in systems of this type.

The principal object of the present invention is to provide an improved method and apparatus for the transmission of intelligence.

Further and other objects of the present invention will hereinafter become apparent in the accompanying specification and claims and shown in the drawing which by way of illustration is what is now considered to be the best mode in which it. has been contemplated applying that principle. @ther embodiments of the invention employing the same or equivalent principle may be used and structural changes made as desired by those skilled in the art without departing from the'present invention and within the spirit of the appended claims.

One form of the invention is fully disclosed in the following description and in the accompanying drawing which shows a diagrammatic view of the apparatus.

Referring now to the drawing, the transmitting and receiving units include a conventional or modified typewriter having a series of lettered and numbered pivoted key bars I. 0ver the bars is mounted a roll 2 held in a slidable carriage (not shown) in the usual manner so that it is moved one space on depression of any key bar. Each key bar has associated therewith a type bar 3 adapted to strike against the roll 2 on depression of the corresponding key bar. 7 This action. is effected through a suitable linkage 4, between each key bar and its corresponding type bar. A sending distributor 6 carries a series of spaced contacts 6 corresponding respectively to the various characters on the type bars i. tacts are engaged in rather rapid succession by a rotary contact arm I driven by a motor 8, which is in synchronism with the similar device at the other end of the transmission circuit and which The conis fully described in the prior application stated 7 hereinbef ore.

Each of the key bars I is comprised in a branch condenser circuit embodying a common conductor I! in which is comprised a condenser charging battery l3. A line i5 is extended from one side of the battery l3 and is branched separately to a series of contacts l6 disposed respectively beneath the key bars I and normally spaced from the latter when the bars are in their normal or corresponding b anch condenser circuit will be completed at the contact l6 engaged by the deto fixed contacts 2| positioned over the key bars l. The latter contacts are engaged by the corresponding bars I when the latter are in raised or released position and at such time close a sending circuit consisting of the conductor i9, a corresponding condenser l8, contact 2i, conductor 20, contact 6, and arm TI.

The radio transmitter 22 has one of its output terminals connected to an antenna 23 and its other output terminal 2 3 grounded in the usual manner. The input terminals are connected to the armature 25 of relay 9 and its contact it which normally remain in engagement so that the input circuit of the transmitter remains closed during the timed intervals the relay 9 remains deenergized and in this manner, the transmitter 22 is adapted to radiate a continuous or prolonged impulse.

In the operation of the device as thus far described, it will be seen that the depression of a key bar l first breaks the corresponding branch circuit at the contact 2i and closes one of the branch condenser circuits to charge the corresponding condenser it. On return of the key bar 5 into engagement with its contact M, the sending circuit will be closed when the arm i reaches the corresponding contact 6 on the disk 5.

The closing of the sending circuit in this manner energizes and operates the relay 9 to open its normally closed contact l0 causing the transmitter input circuit to be deenergized to terminate the prolonged or continuous transmitted impulses at the particular point in the predetermined timed interval cycle to represent the particular character initiating the relay energizing or transmitter deenergizing'impulse, thus creating a void impulse or timed interval during the continuous transmission of the continuous impulse.

A description of the receiving apparatus and its operation to effect the recording of a character corresponding to the character setting up the void condition described will now be explained. I

The receiving circuit of the apparatus includes a receiver 30 having one of its input terminals grounded at at and its other input terminal connected to an antenna 32 and adapted to receive the prolonged or continuous impulse referred to and sent out from the antenna 23 in the usual manner. solenoid 38 adapted to operate on a plunger 39 in the form of a finger depending from'the bar so that when a given solenoid is energized by means presently to be described, the corresponding key bar will be depressed to actuate the corresponding type lever 3. The receiving circuit is governed by a disk or distributor 40 carrying spaced contacts il corresponding in number and position to the contacts 6 on the disk 5. A contact arm 62 rides over the contacts Q0 and is driven by a mechanism such as a motor M and rotating in synchronism with the motor 8, in a manner similar to the described method in the said prior application.

One terminal of each of the solenoids 38 is separately connected to one of the corresponding contacts M by conductors t6, the other solenoid Beneath each of the key bars 6 is a terminals are joined by a common conductor to the output of a suitable amplifier represented by way of example by the thermionic tube with its anode connected to the said common conductor.

The output of the receiver 30 has embodied therein a suitable light source such as a neon tube 50 adapted to be energized by the transmitted continuous or prolonged impulse impressed on the receiver 30. The light source during these periods of energization is directed upon and adapted to activate the photo cell 5| in a well known manner. The grid of the amplifier tube 618 is connected in a standard manner to the anode circuit of the photo cell 5l so that so long as the cell 5! is energized by the light source 50 the grid of the tube 68 is biased to a degree that the current in the amplifier plate circuit is decreased so as to be ineffective to energize and operate the solenoids 38 during the intervals the arm 12 engages the respective contacts ti. However, when a void impulse is transmitted and re ceived, that is the discontinuance of the prolonged impulse, the light source 50 becomes deenergiz ed and in turn the photo cell 5| becomes deener gized tending to make the grid of the amplifier more positive with respect to the plate and increase the current flow in the plate circuit to the extent that upon the engagement of a particular contact ll at that moment by the contact arm :32 the corresponding solenoid embodied in the completed circuit is sufliciently energized to operate the said solenoid.

Therefore it is seen that each time the prolonged or continuous impulse is discontinued the solenoid 38 included in the circuit completed by the contact armfiZ and contacts M is energized sutficiently by the current flow from the amplifier 48 to operate the said solenoid. The character corresponding to this contact M is printed on the roll 2 at the receiving station. These characters printed will appear in the same order in which they are sent inasmuch as the arms I and 32 are in synchronism and always in like relation to the contacts engaged thereby, and since the discontinuance of the prolonged impulse it created only when the arm I at the sending station engages the contact 6, corresponding to the key which has been depressed.

It will be noticed that the receiving contacts at are of greater length circumferentially than the sending contacts 6. In fact, the latter are made as short as possible in order that the initiated impulse and created void impulse may be instantaneous. The longer receiving contacts 4H, however, hold the receiving circuit closed for an interval suificient to enable energization of the solenoids 38 and operation of the type bars 3, as well as allow for slight inaccuracies in the synchronism of the transmitting and 'receiving arms I and d2 respectively.

While there has been shown and described and pointed out the fundamental novel features of the invention as applied to a single modification, it will be understood that various omissions and substitutions and changes in the form and details of the device illustrated and in its operation may be made by those skilled in the art without departing. from the spirit of the invention. It is the intention therefore to be limited only as indicated by the scope of the following claims.

What is claimed is:

1. A communication system of the character described comprising, in combination, means to receive a continuous or prolonged impulse, the discontinuance of which at predetermined timed anacao intervals representing various character designation signals, a light source controlled by said receivingmeans, a circuit including light sensitive means controlled by said light source so that upon discontinuance of the prolonged impulse a source of current energizes said circuit, and recording means controlled by said circuit and operated in accordance with the character signals upon energization of said circuit.

2. A communication system of the character described comprising, in combination, means to receive a continuous or prolonged impulse, the discontinuance of which at predetermined timed intervals representing various character designation signals, a light source energized by said receiving means during the transmission of the prolonged impulse, a circuit including light sensitive means controlled by said light source so that upon discontinuance of the prolonged impulse a source of current energizes said circuit, and recording means controlled by said circuit and operated in accordance with the character signals upon energization of said circuit.

3. A communication system of the character described comprising, in combination, means to receive a continuous or prolonged impulse, the discontinuance of which at predetermined timed intervals representing various character designation signals, a light source controlled by said receiving means, a circuit including light sensitive means controlled by said light source so that upon discontinuance of the prolonged impulse a source of current, energizes said circuit, means operating in synchronism with said character signals, a recording device controlled conjointly by the last mentioned means and said circuit to operate the recording device in accordance with the character signals upon energization of said circuit.

GLENN W. WATSON. 

